It is well known that front end loaders may be used for a multiplicity of purposes depending upon the attachment or implement employed. In effect, the front end loader serves as a power source adapted for powering or driving buckets, forks, plows, scoops, and various other types of implements. As is well known in the art, such implements are removably interconnected to the front end loader by means of an appropriate coupler. The versatility and efficiency of the front end loader and the various attachments is known to be a function of the coupler employed. It is most desirable that the implement be readily engaged and disengaged with the front end loader in such a manner that, once engaged, the implement operates as though it were directly attached to the front end loader with little or no loss of performance or productivity being experienced as a result of the presence of the coupler.
Previously, a large number of coupler systems have been known for interconnecting implements with front end loaders. The present standard for "quick couplers" is set forth in U.S. Pat. No. 4,708,579 assigned to JRB Company, Inc. of Akron, Ohio, the assignee of the instant application. It is also known in the art to employ a cam lock type of coupler. Neither of these prior art systems provide a coupler which is both self tightening and self adjusting. It is well known that slack is present within a coupler as a result of manufacturing tolerances and the wear which results from use. Coupling pins, holes, stop blocks, and the like which are presented between the male and female portions of the coupler tend to wear with use. Such wear reduces the effectiveness and efficiency of the coupler system and, upon reaching an excessive level, requires replacement of the coupler or repair of portions thereof.
Even the prior art cam lock couplers are complex in design and implementation, resulting in an increase in costs and a reduction in efficiency. Such cam lock systems are also given to wear and alignment problems as presented above. In like manner, couplers made according to the aforementioned patent, while providing the most efficient systems presently available, are also given to wear and resulting alignment problems.
It is recognized that there is a need in the art for a coupler system for front end loaders which is self tightening and self adjusting, automatically compensating for wear and manufacturing tolerances within the coupler system. There is a further need for a coupler which provides multiple points of load bearing contact spaced apart within the coupler system to receive and bear the load transmitted thereto. In other words, the heavy loads passing from the implement to the front end loader arms must necessarily pass through the coupler system. It is most desirable that such forces be passed through a multiplicity of points, diminishing the load at any particular point, assuring the maintenance of system integrity. There is further a need in the art for a coupler system in which forceful engagement between the male and female portions of the coupler are continuously urged by a mechanical biasing means, disengagement of the coupler necessitating the application of manual, pneumatic, or hydraulic force.